% BUTTERFILT
%
% [ outdata ] = butterfilt( indata , Fs , Forder , Fcutoff , type )
%
% Filters input data using a high- or low-pass butterworth filter of a
% specified order.  If a bandpass filter is specified, Fcutoff must be a 
% vector containing the high- and low-pass frequencies, [Flow Fhigh].
%
% type = 'bandpass' --> bandpass
% type = 'low' --> lowpass
% type = 'high' -> highpass



function [ outdata ] = butterfilt( indata , Fs , Forder , Fcutoff , type )

%-----filter limit
filtlimit = Fcutoff / ( Fs / 2 ) ;

%-----calculate filter coeficients
if strcmp( type , 'bandpass' )
    [ coefB, coefA ] = butter( Forder , filtlimit );
else
    [ coefB, coefA ] = butter( Forder , filtlimit , type);
end
%-----filter data
outdata = filter( coefB, coefA , indata );

end